The Henrietta Leavitt Flat Screen Space Theater is named for an American astronomer working at the Harvard Observatory in the beginning of this century. The site is authored by Carolyn Collins Petersen, an accomplished astronomy writer and part-time Hubble researcher. Carolyn takes viewers to "The Planetarium Show That Never Ends," where various heavenly bodies are displayed and described in...

"This site is a tool for amateur astronomers who love to pursue deep sky objects. It employs a web-based version of the Saguaro Astronomy Club's database (ver 7.2), consisting of over 10,000 records. This online version of the SAC database allows amateur astronomers to compile detailed and customized observing lists," says the text on the Deep Sky Database homepage maintained by members of the...

The Virtual Sky Viewer is sponsored by The Center for Advanced Computing Research at the California Institute of Technology and the Microsoft Corporation. The Web site allows users to view "stunning, seamless images of the night sky; not just an album of popular places, but the entire northern sky at high resolution". Although reading the help link before attempting to use the viewer is recommend,...

The earth's diameter is 12,756.3 km and its revolution period is 1 year. You probably knew the last fact, but most likely not the first. The Web site Absolutely Astronomy can provide this and a large amount of other facts about planets, moons, stars, constellations, messier objects, nebulas, and galaxies. Visitors can browse via the pull-down menus or search by a particular question. The basic...

This Topic in Depth presents the science and research of galaxies. First, the University of Cambridge offers clear, logical descriptions and images of the Milky Way, spiral and elliptical galaxies, clusters, and dark matter of the Universe (1). Users can also find educational tutorials on many other cosmology topics. Next, the Space Telescope Science Institute's "Galaxies Galore, Games and More is...